But with major pop culture icons, the assumption has to be that the great majority of people who see your Bart-bedecked paraphernalia are already familiar with the dude. So why drop jack on a Cartman plush doll? --RWH

Couldn't the reason be as simple as that the Mr. T aficionado likes to see Mr. T, that seeing Mr. T makes him happy, therefore he surrounds himself with images of Mr. T? True, there's no need for these displays to be public; a private shrine should do the trick. Perhaps the admen have calculated that they'll get more mileage from their kitsch if they license products more likely to be seen in public, like T-shirts. Bumper stickers, in particular, aren't designed to be seen by their owners. I think they've tapped into something primal and profitable: Ha-ha, it's a Bart sticker! Bart's funny. I like Bart, therefore I like this Bart sticker. I can buy this Bart sticker, therefore I will buy this Bart sticker.

One could argue which of those two "therefores" is more irrational. The first one seems to follow this logic: "Oh look, they make labels that adhere to motorized conveyances. And this one has my favorite cartoon character on it, so it must be the one for me." Pretty crazy. The second one is hard to believe too, but studies have demonstrated that the mere fact that something is available to purchase makes it more desirable to purchase.